Thread by @WuidQ

#idgrandrounds
Case presentation:
1/3 | 18/M CC: "most severe headache"

Late summer in IL. 1 wk ago, +fever, myalgia, leg rash. SSX resolved after 4 d. 3 d later, fever recurred (low grade) but now w/ headache. Day of admission, "worse headache" & delirium. Hospital admission.

2/3 Case presentation:

UTD w/ immunization. No PMH/meds. Not sexually active. Works in Walmart. Reported hiking 1 wk prior, +tick/mosquito bites, +swimming in man-made lake. Has dogs, cats, pet lizard. No sick contacts.

3/3 Case presentation:

Exam: supple neck, confused.

WBC 14, Plt 610. CMP n/l. CSF: WBC 320 (78%L), n/l gluc/TP. CSF HSV/VZV/enterovirus/bacterial Cx (-). RPR/HIV(-). Resp viral panel(-).

Diagnosis? Differentials?
@TxID_Edu @DocWoc71 @BradCutrellMD @Cortes_Penfield @jdcooperid

@TxID_Edu @DocWoc71 @BradCutrellMD @Cortes_Penfield @jdcooperid 1/10
Patient was started on doxycycline for presumed tickborne illness. Defervesced, SSX resolved in 2 days.

Ehrlichia PCR & CSF arboviral/WNV panel (-). Microscopic agglutination test (MAT) for Lepto >1:800.

CASE RESOLUTION: Leptospirosis

2/10
Our usual illness script for leptospirosis is somebody w/:

✔️ Weil's disease: hepatic + renal failure
✔️ pulmonary hemorrhage
✔️ conjunctival suffusion
✔️ myalgia (esp calf tenderness)
✔️ exposure to rodents, flooding

Will talk more about conjunctival suffusion in #idmesh

3/10
However, leptospirosis has a broad range of clinical presentations (subclinical in 90% & severe complications rare).

Also important to include in the illness script of leptospirosis the following:

1⃣ Biphasic pattern
2⃣ Aseptic meningitis

4/10
1⃣ Biphasic illness

Depicted in the infographics 👇.

Not specific to leptospirosis. Others diseases classically described as biphasic include:

▪️ Most flaviviruses (dengue, WNV, yellow fever)
▪️ Chikungunya
▪️ Coltivirus (Colorado tick fever)

5/10
It is important to note however, that it maybe difficult to appreciate the biphasic pattern of an illness because of: use of antipyretics, partial treatment w/ antibiotics, populations that may not mount fever (e.g. some elderly patients).

6/10
2⃣ Aseptic meningitis

Occurs during the immune phase in up to 50% of patients.
ncbi.nlm.nih.gov/pubmed/11524519

Marked by lymphocytic predominant pleocytosis, mildly elevated TP, & n/l glucose.

✔️ Need to be aware of this as it is a TREATABLE cause of aseptic meningitis.

7/10
A good illness script will only materialize after a thorough history and exam.

The infographics 👇 can help one create a good and compelling infectious disease history. Exposure history is one of the critical components of an ID history.

8/10
Lastly, I wanna say that doxycycline was started in this patient because of a suspicion for tickborne illness.

▪️ During the summer, in febrile patients, esp those w/ ⬇️ WBC/plt, ⬆️ LFT 👉 low threshold for starting doxycycline; can be life-saving (esp in RMSF cases)

9/10
▪️ None of the tests have 100% Sn for tickborne infections during acute illness; if tests (-) but patient is responding well to doxycycline, can usually complete course of Tx; can re-check serology after 4 weeks to confirm diagnosis

10/10
Agree! Lots of DDX for this case. Incredible job @TxID_Edu @CathalOBroin @k_vaishnani @mangarone23 @jdcooperid @marcolorio! You guys got it w/ 100% precision.

For more on leptospirosis, covered here last year.

Review:

https://twitter.com/WuidQ/status/1064606504555347968?s=20